Earlier this year, Microsoft released an update to ADFS (RU1) which introduced some new features of which Client Access Policies were one. Client Access Policies allow you to restrict access to Office 365 services based on the location (IP) of your clients.
To find out more, have a look at the following TechNet article:
Unfortunately, configuring these policies is rather difficult and cumbersome, due to the regular expressions it uses. At least that was until recently, when I came across this interesting tool that helps building (complex) Client Access Policies.
The policy builder tool will allow you to graphically design and configure policies in an easy and straightforward manner:
To find out more about the tool and to download it, visit the following page: